Applicant claims the priority of German patent application, Ser No. 100 06 635.6 filed Feb. 14, 2000.
This invention relates generally to a fuel tank having fuel system components contained therein and a method of making the fuel tank.
In conventional fuel tanks certain components essential to the operation of the fuel system, such as the fuel pump, fuel filter, fuel level sensor for the fuel gauge, and one or more vent valves are disposed within the tank after the fuel tank is formed. Additionally, electrical lines and lines for transporting fuel, or fuel vapors are needed to interconnect the components with each other and with the remainder of the fuel system outside of the fuel tank. In the past, these components and corresponding lines have been separately mounted within or onto the tank using separate individual holders. The mounting of the components is performed after the fuel tank is produced in its final shape, such as, for example, by blow molding. In order to make this possible, a number of openings must be provided in the walls of the fuel tank, and the openings must be large enough to enable the insertion and mounting of the components in the tank. Additional components such as safety valves, hoses, sensors and the like are mounted on the outside of the tank.
In addition to the significant effort of designing components to fit in the tank and actually mounting the components in or on the tank, the openings in the tank wall increase the hydrocarbon and other emissions from the fuel tank. Moreover, due to the components mounted on the outside of the tank, the space required for mounting the tank in the vehicle is increased.
A fuel tank has a plurality of fuel system components therein and is formed by incorporating the fuel system components into the fuel tank as it is being formed. The fuel system components may be disposed within a parison which is subsequently molded to form the fuel tank. The fuel system components may be mounted on a carrier and then the carrier with the fuel system components thereon is disposed in the parison which is subsequently molded to form the fuel tank. Accordingly, the fuel system components preferably on the carrier are within the formed fuel tank. Desirably, all electrical, fuel and vapor lines may extend out of a single opening of the fuel tank to reduce openings in the formed fuel tank.
The carrier element may also function as a baffle or divider plate, which divides the volume of the tank into smaller portions and eliminates or reduces surging or splashing of large amounts of fuel. Advantageously, the carrier is at least locally connected, and preferably bonded or welded, to the inside of the fuel tank. To this end, the carrier may have a plurality of feet or connecting elements spaced along its edges, which consist of a plastic material that is weldable or bondable to the inside of the tank wall. The remainder of the carrier may therefore consist of a plastic material, which is not weldable or bondable to the material of the tank, or it may consist of a metal. The feet may also be formed as separate connecting elements, which are, for example, clipped or molded onto the carrier. According to a preferred embodiment of the invention, a gap is formed between the inside wall of the tank and the carrier element in the regions between two adjacent feet, through which fuel may flow, so that an even fuel level is attained within the divided portions of the tank. The function of a splash reducing baffle or divider is best achieved when the carrier is disposed essentially transversely with respect to the longitudinal axis of the tank as it is mounted in a vehicle. The shape of the carrier is not limited to an essentially flat shape, rather it may be of advantage if it has a cross section which is wavy, zigzagged, meandering or the like.
In general, the fuel system components preferably have a life expectancy that makes replacement during the service life of the vehicle unnecessary. In the event a component becomes defective, preferably it may be easily removed from the carrier and the tank and easily replaced by a new unit. According to a preferred embodiment of the invention the carrier therefore has guideways for connectors of the fuel system components which lead from the respective mounting position of each component to a closable service opening or a cap of the tank. This makes it possible to replace components which are not located in the direct vicinity of the fuel tank opening. The guideways may be formed as undercut grooves or slots transversing the carrier or as guide rails along which the connectors of the components are guided.
A number of the components, for example a fuel pump and a fuel filter, may be connected to each other by means of fuel lines. A further simplification of the arrangement and a saving in materials is achieved when the carrier comprises internal passages or channels, which connect the components to each other and to other fuel system components. These internal passages or channels are used in place of the otherwise present conduits or lines; i.e. the fuel and/or vapor is led through the passages or channels within the carrier. Only short connecting lines, fittings or adapters between the respective component and the carrier are then needed.
One method for producing a fuel tank according to the invention comprises the following steps: First, all of the fuel system components which are to be disposed inside the fuel tank are mounted on each other or on the carrier. This pre-assembled unit is then placed inside of a parison, which is subsequently blow-molded in the usual manner. During the blow molding process, the feet or connecting elements of the carrier are engaged with and preferably become attached, and may be welded, bonded or adhered, to the inside of the fuel tank wall. The fuel tank created in this manner is ready to be mounted in a vehicle with only a few further assembly steps.
Objects, features and advantages of the invention include providing a fuel tank and method of making it which reduces the time, labor and cost to form a fuel tank with necessary fuel system components mounted therein, integrates the fuel system components in the tank in a simple manner, reduces the number of openings needed in the fuel tank, reduces the emissions from the fuel tank, reduces sloshing or splashing of liquid fuel in the fuel tank, facilitates mounting fuel system components in any desired location in the tank, facilitates mounting and assembly of the fuel tank into a vehicle, is of relatively simple design, economical manufacture and assembly and in service has a long, useful life.